World leaders expressed dismay, sadness and solidarity with France over the Nice attack, carried out by a man who drove a lorry into crowds of people celebrating France's national day, killing at least 80 people.
A statement issued by Taoiseach Enda Kenny read: “I am deeply shocked and saddened at this horrific attack in Nice.
“Once again innocent people have been targeted at an occasion of joy and celebration.
“French people have suffered appallingly and have again been the victim of cynical, and wanton violence. We cannot and will not yield to this malevolence.
“On behalf of myself, the Government and the Irish people I want to express our deepest sympathies and our solidarity to President Hollande and to all of France.”
President Barack Obama condemned what he said "appears to be a horrific terrorist attack" in Nice.
"Our thoughts and prayers are with the families and other loved-ones of those killed."
Secretary of State John Kerry called it a "horrendous attack in Nice. ... I was proud to stand alongside French leaders earlier today at Bastille Day celebrations in Paris, and the United States will continue to stand firmly with the French people during this time of tragedy".
Both presidential candidates also condemned the attacks, with Republican Donald Trump declaring "this is war" and Democrat Hillary Clinton vowing "we will not be intimidated".
Mrs Clinton said "every American stands in strong solidarity with the people of France, and we say with one voice: we will not be intimidated. We will never allow terrorists to undermine the egalitarian and democratic values that underpin our very way of life".
Mr Trump, who postponed plans to announce his vice-presidential pick because of the attacks, said: "This is war. If you look at it, this is war coming from all different parts. And frankly it's war and we're dealing with people without uniforms."
Former House of Representatives speaker Newt Gingrich reacted to the attack by calling for the expulsion of any Muslim who believed in Sharia law from the US.
The former Georgia congressman, who is being considered as a Republican White House running mate for Donald Trump, told Fox News Channel's Hannity that the US "should frankly test every person here who is of a Muslim background, and if they believe in Sharia, they should be deported.
"Sharia is incompatible with Western civilisation".
European Council president Donald Tusk expressed consternation that France was attacked on its national day and said the world stands united with the French people.
"It is a tragic paradox that the victims of the attack people celebrating liberty, quality and fraternity. We will stand united with the families of victims, the French people and the government in the fight against violence and hatred," he said at a meeting of Asian and European leaders in the Mongolian capital Ulaanbaatar.
Premier Li Keqiang said "we strongly condemn terrorism of all forms. We express our condolences to the victims and we will fight all kinds of terrorism".
Foreign minister Didier Reynders expressed dismay that France was once again the target of an apparent terrorist attack.
"We condemn such an attack, maybe a terrorist attack, but such an attack in France again," he said.
Foreign minister Julie Bishop said three Australians suffered minor injuries while fleeing the scene.
"It has shocked France, it has rocked it to its core," she said in the Western Australia capital of Perth. "This should have been a time of great national pride and celebration."
Ms Bishop condemned the violence, saying it was a reminder that "no country is immune from terrorist attacks".
"We support our friends and partners in France and we join with others around the world in hoping that this will be the end of this type of horrific incident that is targeted at unarmed civilians," she said.
Foreign minister Jose Manuel Garcia-Margallo said he called his counterparts in France to express his condolences.
"We are very sorry and very much with the French people and the French government," he said in at a meeting of Asian and European leaders in Ulaanbaatar.
Prime minister Taavi Roivs condemned "a terrible attack on innocent people celebrating their national day. Today, we all stand together with the French people".
Prime minister Narendra Modi condemned what he called a mindless attack.
"I am appalled by the horrific attack in Nice. I strongly condemn such mindless acts of violence. My thoughts are with the families of deceased," he said.
"I hope the injured recover soon. India shares the pain and stands firmly with our French sisters and brothers in this hour of immense sadness."